Not in my experience, I had a huge pin cushion that got infected with something and the whole one side of it turned into mush, I took it out the tank and it stank really badly. I cut almost 1/2 of the pin cushion away and placed it back into the tank, it recovered beautifully and after a few months it was looking just as good as it was before, albeit a bit smaller.im following this one cos when it starts rotting or falling apart from one side it is not like an sps that you can frag. if it is sick the whole animal is sick. it needs to heal before being fragged. i would put it in a quaranteen bucket with a high watrr flow and do regular water changes to prevent bacteria levels climbing too much. i would also put a drop of lugols or similar iodine in water.
Not in my experience, I had a huge pin cushion that got infected with something and the whole one side of it turned into mush, I took it out the tank and it stank really badly. I cut almost 1/2 of the pin cushion away and placed it back into the tank, it recovered beautifully and after a few months it was looking just as good as it was before, albeit a bit smaller.